1. Field of the Invention
The present invention relates to disk drives. More particularly, the present invention relates to a disk drive comprising a coating bonded to a printed circuit board assembly.
2. Description of the Prior Art
FIG. 1 shows an exploded view of a prior art disk drive 2 comprising a head disk assembly (HDA) enclosure 4 which houses a disk 6 and an actuator arm 8 for actuating a head 10 radially over the disk 6. The actuator arm 8 is rotated about a pivot 12 by a voice coil motor (VCM) 13, and the disk 4 is rotated about its axis by a spindle motor 14. A printed circuit board assembly (PCBA) 16 is attached to the HDA enclosure 4 using screws or adhesive. Electrical components 18 are typically mounted on a surface of the PCBA 16 facing the HDA enclosure 4, whereas the opposite surface of the PCBA is exposed to the environment. This is illustrated in FIG. 2A which shows a bottom view of the disk drive 2 of FIG. 1, including the exposed surface of the PCBA 16. FIG. 2B shows a side view of the disk drive of FIG. 1, including the PCBA 16 attached to the bottom of the HDA enclosure 4 inside a hollowed area for receiving the PCBA 16.
To protect the electrical leads on the exposed surface of the PCBA 16, the disk drive 2 is typically housed in some sort of enclosure, such as within a PC or an external disk drive housing made of metal or plastic. The disk drive""s enclosure also protects against physical damage to the PCBA 16 and mounted electrical components 18 which is of particular concern in portable applications where the portable device may be dropped. However, if the disk drive""s enclosure is subjected to a substantial physical shock, the shock may still propagate to the PCBA 16 and damage the electrical components 18 even if the enclosure is not actually compromised.
There is, therefore, a need to protect a disk drive against physical shocks which may damage the PCBA and mounted electrical components.
The present invention may be regarded as a disk drive comprising a head disk assembly (HDA) including an enclosure for housing a disk and a head actuated radially over the disk. A printed circuit board assembly (PCBA) is attached to the HDA enclosure, wherein the PCBA comprises at least one attached electrical component. A non-electrically conductive coating is bonded to at least part of the PCBA after attaching the electrical component to the PCBA.
In one embodiment, the coating is bonded to the PCBA by applying the coating in liquid form to the PCBA and then solidifying the coating. In one embodiment, the coating is liquefied through heating and solidified through cooling. In another embodiment, the coating is solidified through a chemical process. In yet another embodiment, the liquefied coating is sprayed onto the PCBA. In yet another embodiment, the PCBA is dipped into the liquefied coating.
In one embodiment, the coating comprises a heat dissipating material. In one embodiment the coating comprises a plastic material, and in one embodiment the coating comprises a polymer material.
In one embodiment, the PCBA forms at least one crevice with respect to the HDA enclosure, and the coating is disposed within at least part of the crevice. In one embodiment, the coating substantially covers the entire PCBA and the entire HDA enclosure.
In one embodiment, the coating is bonded to the PCBA before the PCBA is attached to the HDA enclosure. In an alternative embodiment, the coating is bonded to the PCBA after the PCBA is attached to the HDA enclosure.
The present invention may also be regarded as a method of manufacturing a disk drive. The method comprises the steps of inserting a disk and a head into an enclosure of a head disk assembly (HDA), attaching at least one electrical component to a printed circuit board assembly (PCBA), attaching the PCBA to the HDA enclosure, and bonding a non-electrically conductive coating to at least part of the PCBA after attaching the electrical component to the PCBA.